Controlling device for electric sewing machines



March 25, 1930.

I H. M. STEPHENSON CONTROLLING DEVICE FOR ELECTRIC SEWING MACHINES Filed Nov. 5, 192a lr'lventohz Hugh M- Stephenson. by MW His Attorneg.

Patented Mar. 25, 1930 UNITED STATES PATENT? OFFICE HUGH M. STEPHENSON, OE FORT WAYNE, INDIANA, ASSIGNOR 'IO OENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK CONTROLLING DEVICE FOR'ELEOTRIG SEWING MACHINES Application filed November 8, 1928. Serial No. 317,013.

My invention relates to a controlling device for electric sewing machines having a motor for operating the stitch-forming mechanism thereof.

In operating an electric sewing machine it is necessary to provide for a wide range of variation of speed of the'motor driving the machine, so that the operator can vary the speed to suit the character of the sewing operation. Motors have heretofore been controlled in this way by means of a variable resistor connected in series with the motor and the supply circuit. As both hands are ordinarily required to guide the material being sewn \in the machine, it has been the practice to arrange the controlling resistor in the motor circuit on the floor under the machine and to control the same bymeans of a footpedal. This arrangement is very satisfactory from an operating point of view because it is not fatiguing to the operator of the machine and the resistor can be very readily adjusted to maintain the desired speed of the machine. The arrangement has been subject to the disadvantage, however, that the foot-operated resistor and the long connecting cords could not be conveniently put out of the way when the machine was not in use. It has been proposed to overcome this difficulty by securing the resistor to the machine and providing a lever so arranged that the person using the machine could operate the same by his knee. This is unsatisfactory because it is difiicult to accurately control the speed of the machine, as required, and also soon fatigues the operator because it requires the use of muscles which are ordinarily not used to any great extent.

An object of my invention is to provide a sewing machine construction of this character such that all the advantages of a footoperated resistor can be retained and, at the same time, provide for convenient disposal thereof when the machine is not in use. I accomplish this by providing a sewing machine having a driving motor and a cover for the machine, and a controlling device such as a foot-operated resistor-secured to the cover for controlling the machine. In this wa when the cover is removed from the mac e, it

can be laced beneath the same and the resistor or controlling the motor can be readily operated by means of a foot-pedal, and when the machine is not being used the controlling resistor and the cord connecting the resistor and motor to its supply circuit can be arran ed within the cover.

Another 0 ject of my invention is to provide an arrangement for taking up the cord on flexible conductor connecting the motor to the supply circuit into the cover when the same is arranged on the machine, which is so constructed that when the cover is removed from the machine, the length of cord required to connect themachine to the supply circuit will be withdrawn therefrom.

A further object of my invention is to provide a combined cord reel and controlling resistor connected in circuit therewith which will avoid altogether the necessity of any sliding contact for making the connection between the cord and the terminals of the resistor.

Further objects and advantages of my invention will become apparent, as the following description roceeds, and the features of novelty which c aracterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

In the drawing Fig. 1 is a erspective view of a sewing machine embo ying my invention ;-Fi 2 is a transverse section of the sewing mac ine cover on the'line 2-2 of Fig. 1, partly broken away to more clearly show the construction; Fig. 3 is a section on the line 33 of Fig. 2, and Fig.4 is a diagrammatic view of the circuits including the electric motor for driving the machine, its controlling resistor and the electric light which is arranged on the arm of the machine for illuminating the cloth plate of the machine.

Referring to the drawing the sewing machine, in connection with which I have i1 lustrated my invention, includes a bedlate 10 and an arm 11 having the usual stitchforming mechanism supported thereby which is driven by an electric motor 12 secured beneath the bed-plate 10. An electric light 13 is secured to the arm 11 of the machine and arranged to illuminate the bed-plate 10 adjacent the needle-bar. ,The machine is also provided with a cover 14 of the usual form which is arranged over the machine when it is not in use. The electric motor 12 is,

adapted to be connected to the supply circuit by the cord orjlexible conductor 15, and is controlled by a variable resistor 16 connected in the circuit with the motor and the cord or flexible conductorl5, as shown in Fig. 4. In accordance with m invention the variable resistor 16 is secure inside of the sewing matake-up device may be of any suitable form,

in the present embodiment of my invention it comprlses a reel including a rotatable member 18 having grooves 19 and 20 in which the cord 15 is wound. The member 18 is rotatably mounted on the pivotal support 21 secured to a casing 22 attached to the inside of the cover 14 and a helical spring 23 is connected between the member 18 and the pivotal support 21 so that it tends to wind the cord 15 in the grooves 19 and 20. By this arrangement,

when the cover 14 is placed on the machine, the member 18 will be rotated by the spring 23-to wind the cord 15 in the grooves 19 and 20 so as to withdraw the same entirely within the cover 14.

In order to control the motor 12 by means of variable resistance 16 itis connected in the circuit with the cord and the motor, as shown in Fig. 4. I avoid the necessity of using sliding contacts connecting the terminals of the resistor 16 in circuit with the motor by arranging the resistor inside of the rotatable member 18 of the reel, and arrange the same in circuit with one of the leads of the cord 15 by connecting a strand 15' of the cord directly thereto and connecting the strand 15 to the sliding contact 16' thereof. The footpedal 17 is attached to the cover 14 and connected to the sliding contact 16 by a link 24, the foot-pedal 17 having a s ring 25 thereon for normally retaining the s iding contact in the off-position when the cover is arranged to be operated by the foot-pedal. It is necessary that the resistor 16 be retained in a definite relation to the foot-pedal 17 when it is being used to control the motor. I do this by providing a lockfor retaining the rotatable member 18 in the position shown in Fig. 2. The particular lock which I have shown in the present embodiment of my invention comprises a pin 26 having a sprin 27 tending to ring it into engagement wit the notch 28 in the rotatable member 18. The pin 26 is adapted to be retained out of engagement with the rotatable member 18 when the cord 15 is being wound thereon by a latch-pin 29 engaging the body of thelock which is moved into a slot 30 formed in the body of the lock, as shown in Fig. 3, whenit is desired to lock the rotatable member 18. g

It will be observed that in va ing the resistor 16 to control the motor 12 t at the voltage across the terminals of the motor will vary over a wide range. This would not be suitable for the light 13 because of the resulting variation in intensity of the illumination of the cloth plate. I avoid this by connecting one terminal of the light to the strand 15 of the cord 15 which is directly connected to the motor at 32, and connecting the other terminal thereof to the strand 15" of the cord at 33 which is on the constant potential side of the resistor 16 connected directly to the supply circuit. In this way the intensity of illumination of light 13 is maintained substantially constant independently of the variations of the resistor 16 required to control the motor 12 as desired. This circuit arrangement r uires two strands of the conductor from t e end of the cord 15 which is adapted to be plugged into or connected to a supply circuit and three strands extending from the reel to the machine. I prefer to wind the two strand portion of the cord connected to the supply circuit on the groove 20 in the rotatable member 18 of the reel, and

to wind the three strand portion of the cord extending from the reel on the groove 19. I

simplify the construction by attaching the to the resistor 16.

When it is desired to operate the sewing machine I remove the cover 14 thereof, set the pin 26 so that the latch-pin 29 is in line with the slot 30, and then place the cover beneath the machine, as shown in Fig. 1. As the three-strand portion of the cord 15 is directly attached to the machine, the movement of the cover away from the head unwinds the cord from the reel by turning the rotatable member 18 against the force of the spring 23 which, at the same time, unreels the two-strand portion of the cord which is adapted to be plugged into or connected to the supply circuit. During this movement of the rotatable member 18 the notch 28 snaps over the end of the pin 26 against the action of the spring 27 at each revolution of the rotatable member. When sufiicient length of cord has been unreeled, I allow the reel to reverse until the pin 26 drops into the notch 28 formed in the rotatable member 18. This locks the reel in the position shown in Fig. 2 so that the machine can be controlled by operating the foot-pedal 17. I then plug the end of the cord into the supply circuit and the machine is ready for operation, as shown in Fig. 1. After the sewing operation is comthat the pin 29 holds the pin 26 in retracted f position. This releases the rotatable member 18 so that it is free to turn under the action of the spring 23 and wind the cord 15 thereon. I replace the cover 14 on the machine and the spring 23 turns the rotatable member 18 of the reel so as to draw the cord 15 entirely within the cover.

It will thus be seen that I have provided a sim le and convenient arrangement for control ing a sewing machine which possesses all of the advantages of the ordinary foot-pedal cont-rolled resistor and which is entirely out of the way when the machine is not in use.

Modifications of the embodiment of my invention above set forth will occur to those skilled in the art, so that I do not desire my invention to be limited to the particular arrangement shown and described, and I intend in t e appended claims to cover all modifications thereof which do -not depart from the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. A sewing machine having an electric motor for driving the same, a removable cover for said machine, and means secured to said cover for controlling said motor, said controlling means being adapted to be operated when said cover is removed from said machine.

2. A sewing machine having an electric motor for driving the same, a flexible conductor adapted to connect said motor to'an electric circuit, a removable cover for said machine, and means connected in a circuit with said flexible conductor and secured to said cover for controlling said motor, said controlling means being adapted tobe footoperated when said cover is removed from said machine.

3. A sewing machine having an electric motor for driving the same, a flexible conductor adapted to connect said motor to an electric circuit, a. cover for said machine, means connected in a circuit with said flexible conductor and secured to said cover for controlling said motor, and a take-up device for said flexible conductor secured to said cover.

4. A sewing machine having a cover and an electric motor for driving the same, a flexible conductor adapted to connect'said motor to an electric circuit, means connected in a circuit with said flexible conductor for controlling said motor, said controllin means including avariable resistor secure to said cover, and a take-up device for said flexible conductor secured to said cover.

5. A' sewing machine having a cover and an electric motor for driving the same, a flexible conductor adapted to connect said motor to an electric circuit, means connected in a circuit with said flexible conductor for controlling said motor, and a take-up device for said flexible conductor secured to said cover, said controlling means includin a variable resistor carried by said take-up evice.

6. A sewing machine having a cover and an electric motor for driving the same, a flexible conductor adapted to connect said motor to an electric circuit, means connected in a circuit with said flexible conductor for controlling said motor, and a take-up device for said flexible conductor secured to' said cover, said controlling means including a variable resistor carried by said take-up device and an operating member for said resistor adapted to be foot-operated when said cover is removed from said machine.

7. A sewing machine having a cover and an electric motor for driving the same, a flexible conductor adapted to connect said motor to an electric circuit, a reel secured to said cover arranged to take up said flexible conductor, a variable resistor connected in a circuit with said motor for controlling the same said resistor being secured to said reel, an means including an operating member secured to said cover for adjusting said resistor.

8. A sewing machine having a cover and an electric motor for driving the same, a flexible conductor adapted to connect said motor to an electric circuit, a reel secured to said cover and arranged to take up said flexible conductor, a variable resistor connected in a circuit with said motor for controlling the same, said resistor being secured to said reel, and means including an operating member secured to said cover for adjusting said resistor and adapted to be foot-operated when said cover is removed from said machine.

9. A sewing machine having a cover and an electric motor for driving the same, a flexible conductor adapted to connect said motor to an electric circuit, a reel secured to said cover and comprising a rotatable member, said flexible conductor being secured to said member and arranged to be wound thereon, a variable resistor connected in a circuit with said flexible conductor and said motor for controlling the latter, said resistor being se cured to said reel, and means including an operating member secured to said cover for adjusting said resistor.

10. A sewing machine motor for driving the same, a flexible conductor adapted to-connect said motor to an electric circuit, a cover for said machine, and

having an electric a take-up device for said flexible conductor secured to said cover.

11. A sewing machine having an electric motor for driving the same a flexible conductor adapted to connect said motor to an electric circuit, a cover for said machine, and a take-up device for said flexible conductor se cured to said cover the ortion of said flexible conductor intermediate the ends thereof being secured to said take-up device.

12. A reel comprising a rotatable member,

a flexible conductor adapted to be wound thereon, and a variable resistor carried b said member and connected in a circuit wit said conductor.

13. A reel comprising a rotatable member,

a flexible conductor adapted to be wound thereon, a variable resistor carried by said member and connected in a circuit with said conductor, and means supported independently of said member for ad ustlng said resistor.

14. A reel comprising a rotatable member a flexible conductor adapted to be woun 2s thereon, a variable resistor carried, by sa d member and connected in a circuit with said conductor, said resistor including a shding contact for adjusting the same, means suported independently of said member for adusting said contact, and means for preventing movement of said member during actuation of said adjusting means.

15. A reel comprising a rotatable member, a flexible conductor adapted to be wound thereon, a variable resistor carried by said member and connected in a circuit with said conductor, said resistor including a sliding contact for adjusting the same, means supported independently of said member for moving said contact to adjust said resistor, a spring for normally retaining said flexible conductor wound on said member, and means for preventing movement of said member during actuation of said adjusting means.

16. A sewin machine having a cover, an electric motor %or driving the same, a flexible conductor adapted to connect said motor to an electric circuit, a reel secured to said cover, said flexible conductor being secured intermediate the ends thereof to said reel, means including a spring tending to wind said flexible conductor on said reel, a variable resistor carried by said reel and connected in a circuit with said motor for controlling the same, and

cured to said cover for adjusting said resistor.

17. A sewing machine having a cover, an

diate the ends thereof to said reel, means including a spring tending to wind-said flexible conductor on sald reel, 9. variable resistor carmeans including an operating member seried by said reel and connected in a circuit with said motor for controllingthe same, and

means including an operating member secured to said cover for adjusting said resistor, said operating member being adapted to be foot-operated when said cover is removed from said machine.

18. A sewing machine having a cover and an electric motor for driving the same, a flexible conductor having one end connected to said motor and the other free end adapted to be connected to an electric circuit, a reel secured to said cover, said flexible conductor being secured intermediate the ends thereof to said reel, means includin a spring tending to wind both ends of said exible conductor, on said reel when said cover is placed on said machine and to be unwound therefrom by the tension of the cord when said cover is removed from the machine, a variable resistor carried by said reel and connected in a circuit with said motor for controlling thesame, and means including an operating member secured to said cover for adjusting said resistor.

19. A sewing machine having an electric light for illuminating the work therein, and a cover for the machine, an electric motor for driving the machine, a flexible conductor adapted to connect said motor to an electric circuit, a variable resistor secured to said cover, said resistor being connected in a circuit with said flexible conductor and said motor for controlling the latter, and a connection from the constant potential end of said resistor to said electric li ht for maintaining the illumination thereof constant independently of variations in said resistor for controllin said motor.

20. sewing machine having an electric light for illuminating the work therein, and a cover for the machine, an electric motor for driving the machine, a flexible conductor adapted to connect saidmotor to an electric circuit, a variable resistor secured to said cover, said resistor being connected in a circuit with said flexible conductor and said motor for controlling the latter, and said flexible conductor including a connection from the constant potential end of said resistor to said electric light for maintaining the illumination thereof constant, independently of variations in said resistor for controlling said mo- In witness whereof, I have hereunto set my hand this 31st day of October, 1928.

HUGH M. STEPHENSON.

an electric circuit, a reel secured to said cover, said flexlble conductor belng secured mterme- 

